The Synchronization Testing for Multi-Channel Data Acquisition System of SADR

The synthetic aperture digital radiometer (SADR) can achieve the finest resolving power with an antenna array that uses a relatively small number of individual elements, in which the phase coherence is essential to image of SADR. Due to jitter of sampling clock and trigger signal, the multi-channel data acquisition system (MCDAS) is very difficult to sample data simultaneously of different receivers, which will result in correlation loss and blur the imaging of SADR. This paper uses orthogonal transformation method to test the sampling error of MCDAS, to correct the sampling skew by the phase calibration method. Experiment result showed: sampling skew between different channels reduces to 20 ps below after phase calibration.